Field of Invention
The present disclosure relates to a method of fabricating a package substrate. More particularly, the present disclosure relates to a method of fabricating a feature of the capacitance layer embedded inside a package substrate.
Description of Related Art
With the advancement of process techniques for fabricating integrated-circuits (ICs), demands related to improvement of the performance of ICs, such as routing density, transmission rate, and signal interference prevention, as well as other improvements, have become increasingly important. Owing to ICs becoming more and more compactly integrated under the improvement of miniaturization processes, most of the semiconductor packages fabricated by the advanced packaging processes need to adopt an IC carrier interconnected between the IC and the printed circuit board, in which the IC carrier may be regarded as a package substrate. More specifically, some specific fabricating processes need to be implemented on the already-manufactured IC for connecting the IC with other electronic components, such as back end of line (BEOL) process and packaging process among other processes. Interconnecting routes of the IC carrier may be adopted to connect ICs with the printed circuit board, to communicate electrical signals between the ICs and the printed circuit board; and moreover, the IC carrier may further adopt to protect the conductive routes and dissipate heat generated by components within a semiconductor package. As a consequence, when the electrical signals communicated between ICs and the printed circuit board require the IC carrier to transmit electrical signals, the working efficiency of a semiconductor packages is greatly dependent on transmission quality of the IC carrier.
However, an IC carrier fabricated by conventional methods may generate protruding parts inside through holes fabricated within a capacitance film of the, IC carriers while patterning the capacitance film, so that the heat and the exerted-forces generated by subsequent processes may be accumulated on the protruding parts; and moreover, the accumulated heat and the exerted-forces may induce the holes within the capacitance film which may, in turn, become cracked or damaged. Furthermore, the cracked or damaged holes may influence transmission quality of the IC carrier. Therefore, in the conventional fabrication of semiconductor packages and the available structure of semiconductor packages, as described above, apparently there exists inconvenience and defect, which needs further improvement. To deal with the aforesaid problem, practitioners with ordinary skill in the art have striven to attain a solution, though a suitable solution is still to be developed. Therefore, to deal with the aforesaid problem effectively is an important subject of research and development, and also a desired improvement in the art.